Depression and the brain: Study finds sex-specific differences in teens

Research targeting the brain activity of male and female adolescents found that depression may affect their brains in different ways, pointing to a need to better understand major depression across sexes.

The National Institute of Mental Health report that major depression is common among teenagers in the United States. Depression can lead to self-harm, substance abuse, and suicide attempts. According to the American Foundation for Suicide Prevention, more than 12 in every 100,000 people between the age of 15 and 24 took their own lives in 2015.

A study published in Pediatrics in 2016 showed a worrying increase in depressive episodes among U.S. teens and young adults. Teenage depression has been observed to stem from many causes, including social media interactions, concerns about body image, bullying, or academic progress.

But so far, there has been little focus on how male and female teenagers may be affected by depression in different ways.

Dr. Jie-Yu Chuang, of the University of Cambridge in the United Kingdom, and her colleagues set out to understand whether adolescent boys and girls show contrasting responses to depression.

The researchers' findings were recently published in the journal Frontiers in Psychiatry.

Different responses in boys and girls

Previous research, published in The Lancet in 2014, has already shown that girls are more than twice as likely as boys to experience depression. But at the point of this study's conclusion, it remained unclear why the distribution should be so disproportionate. Now, the efforts of Dr. Chuang and colleagues may take us one step closer to the answer.

This new study focused on a population sample of 82 female and 24 male adolescents, all of whom had depression, as well as 24 female and 10 male teenagers with no mental health issues. The latter constituted the control group. All subjects were aged between 11 and 18 years.

The researchers used a method known as the "go/no-go task," paired with functional MRI (fMRI), to measure the different responses in the girls' and boys' brains.

The adolescents were shown a specific sequence of happy, sad, or neutral words. They were then asked to press a button when a particular type of word appeared on the screen, and not to press it when other kinds of words arose.

The participants' brain activity was consistently monitored through fMRI for the duration of the experiment.

It was discovered that the supramarginal gyrus and posterior cingulate cortex areas of the brain responded differently in the case of male and female participants affected by depression. It was also found that older participants took longer to respond to the "happy targets" in the experiment.

The functioning of the two brain regions singled out in the study has been linked to depression by research for a long time. However, it remains unclear what their exact role is in the manifestation of this disorder.

These outcomes, nevertheless, point to a differentiated effect of depression on male and female brains beginning in adolescence.

In Dr. Chuang's words, "Our finding suggests that early in adolescence, depression might affect the brain differently between boys and girls."

The researchers hope that this discovery will prompt a more individualized approach to depression treatment for teenage male and females, leading to more effective prevention strategies of major depression in adulthood.

"Sex-specific treatment and prevention strategies for depression should be considered early in adolescence. Hopefully, these early interventions could alter the disease trajectory before things get worse."

Dr. Jie-Yu Chuang

'Men suffer from persistent depression'

The findings of this study are particularly relevant since, as the authors point out, depression also behaves differently in adult men and women. Though women are diagnosed with depression more often than men, the disorder appears to manifest more consistently over time in males, whereas in females, it is more irregular.

"Men are more liable to suffer from persistent depression, whereas in women depression tends to be more episodic," says Dr. Chuang.

The researchers also acknowledge some areas for improvement in their own study. Mainly, the limitations were linked to the participant population sample, which comprised more female than male volunteers.

The unequal numbers were probably due to depression being more common in females, the researchers explain. They therefore aim to conduct further research on a larger sample of male patients to consolidate their current results.

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